include/i2c.h

   1 /*
   2  * (C) Copyright 2001
   3  * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  *
  23  * The original I2C interface was
  24  *   (C) 2000 by Paolo Scaffardi (arsenio@tin.it)
  25  *   AIRVENT SAM s.p.a - RIMINI(ITALY)
  26  * but has been changed substantially.
  27  */
  28
  29 #ifndef _I2C_H_
  30 #define _I2C_H_
  31
  32 /*
  33  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  34  *
  35  * The implementation MUST NOT use static or global variables if the
  36  * I2C routines are used to read SDRAM configuration information
  37  * because this is done before the memories are initialized. Limited
  38  * use of stack-based variables are OK (the initial stack size is
  39  * limited).
  40  *
  41  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  42  */
  43
  44 /*
  45  * Configuration items.
  46  */
  47 #define I2C_RXTX_LEN    128     /* maximum tx/rx buffer length */
  48
  49 #if defined(CONFIG_I2C_MULTI_BUS)
  50 #define CONFIG_SYS_MAX_I2C_BUS          2
  51 #define I2C_GET_BUS()           i2c_get_bus_num()
  52 #define I2C_SET_BUS(a)          i2c_set_bus_num(a)
  53 #else
  54 #define CONFIG_SYS_MAX_I2C_BUS          1
  55 #define I2C_GET_BUS()           0
  56 #define I2C_SET_BUS(a)
  57 #endif
  58
  59 /* define the I2C bus number for RTC and DTT if not already done */
  60 #if !defined(CONFIG_SYS_RTC_BUS_NUM)
  61 #define CONFIG_SYS_RTC_BUS_NUM          0
  62 #endif
  63 #if !defined(CONFIG_SYS_DTT_BUS_NUM)
  64 #define CONFIG_SYS_DTT_BUS_NUM          0
  65 #endif
  66 #if !defined(CONFIG_SYS_SPD_BUS_NUM)
  67 #define CONFIG_SYS_SPD_BUS_NUM          0
  68 #endif
  69
  70 #ifndef I2C_SOFT_DECLARATIONS
  71 # if defined(CONFIG_MPC8260)
  72 #  define I2C_SOFT_DECLARATIONS volatile ioport_t *iop = ioport_addr((immap_t *)CONFIG_SYS_IMMR, I2C_PORT);
  73 # elif defined(CONFIG_8xx)
  74 #  define I2C_SOFT_DECLARATIONS volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
  75 # else
  76 #  define I2C_SOFT_DECLARATIONS
  77 # endif
  78 #endif
  79
  80 #ifdef CONFIG_8xx
  81 /* Set default value for the I2C bus speed on 8xx. In the
  82  * future, we'll define these in all 8xx board config files.
  83  */
  84 #ifndef CONFIG_SYS_I2C_SPEED
  85 #define CONFIG_SYS_I2C_SPEED    50000
  86 #endif
  87 #endif
  88
  89 /*
  90  * Many boards/controllers/drivers don't support an I2C slave interface so
  91  * provide a default slave address for them for use in common code.  A real
  92  * value for CONFIG_SYS_I2C_SLAVE should be defined for any board which does
  93  * support a slave interface.
  94  */
  95 #ifndef CONFIG_SYS_I2C_SLAVE
  96 #define CONFIG_SYS_I2C_SLAVE    0xfe
  97 #endif
  98
  99 /*
 100  * Initialization, must be called once on start up, may be called
 101  * repeatedly to change the speed and slave addresses.
 102  */
 103 void i2c_init(int speed, int slaveaddr);
 104 #ifdef CONFIG_SYS_I2C_INIT_BOARD
 105 void i2c_init_board(void);
 106 #endif
 107
 108 #if defined(CONFIG_I2C_MUX)
 109
 110 typedef struct _mux {
 111         uchar   chip;
 112         uchar   channel;
 113         char    *name;
 114         struct _mux     *next;
 115 } I2C_MUX;
 116
 117 typedef struct _mux_device {
 118         int     busid;
 119         I2C_MUX *mux;   /* List of muxes, to reach the device */
 120         struct _mux_device      *next;
 121 } I2C_MUX_DEVICE;
 122
 123 int     i2c_mux_add_device(I2C_MUX_DEVICE *dev);
 124
 125 I2C_MUX_DEVICE  *i2c_mux_search_device(int id);
 126 I2C_MUX_DEVICE *i2c_mux_ident_muxstring (uchar *buf);
 127 int i2x_mux_select_mux(int bus);
 128 int i2c_mux_ident_muxstring_f (uchar *buf);
 129 #endif
 130
 131 /*
 132  * Probe the given I2C chip address.  Returns 0 if a chip responded,
 133  * not 0 on failure.
 134  */
 135 int i2c_probe(uchar chip);
 136
 137 /*
 138  * Read/Write interface:
 139  *   chip:    I2C chip address, range 0..127
 140  *   addr:    Memory (register) address within the chip
 141  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
 142  *              memories, 0 for register type devices with only one
 143  *              register)
 144  *   buffer:  Where to read/write the data
 145  *   len:     How many bytes to read/write
 146  *
 147  *   Returns: 0 on success, not 0 on failure
 148  */
 149 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len);
 150 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len);
 151
 152 /*
 153  * Utility routines to read/write registers.
 154  */
 155 static inline u8 i2c_reg_read(u8 addr, u8 reg)
 156 {
 157         u8 buf;
 158
 159 #ifdef CONFIG_8xx
 160         /* MPC8xx needs this.  Maybe one day we can get rid of it. */
 161         i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 162 #endif
 163
 164 #ifdef DEBUG
 165         printf("%s: addr=0x%02x, reg=0x%02x\n", __func__, addr, reg);
 166 #endif
 167
 168         i2c_read(addr, reg, 1, &buf, 1);
 169
 170         return buf;
 171 }
 172
 173 static inline void i2c_reg_write(u8 addr, u8 reg, u8 val)
 174 {
 175 #ifdef CONFIG_8xx
 176         /* MPC8xx needs this.  Maybe one day we can get rid of it. */
 177         i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 178 #endif
 179
 180 #ifdef DEBUG
 181         printf("%s: addr=0x%02x, reg=0x%02x, val=0x%02x\n",
 182                __func__, addr, reg, val);
 183 #endif
 184
 185         i2c_write(addr, reg, 1, &val, 1);
 186 }
 187
 188 /*
 189  * Functions for setting the current I2C bus and its speed
 190  */
 191
 192 /*
 193  * i2c_set_bus_num:
 194  *
 195  *  Change the active I2C bus.  Subsequent read/write calls will
 196  *  go to this one.
 197  *
 198  *      bus - bus index, zero based
 199  *
 200  *      Returns: 0 on success, not 0 on failure
 201  *
 202  */
 203 int i2c_set_bus_num(unsigned int bus);
 204
 205 /*
 206  * i2c_get_bus_num:
 207  *
 208  *  Returns index of currently active I2C bus.  Zero-based.
 209  */
 210
 211 unsigned int i2c_get_bus_num(void);
 212
 213 /*
 214  * i2c_set_bus_speed:
 215  *
 216  *  Change the speed of the active I2C bus
 217  *
 218  *      speed - bus speed in Hz
 219  *
 220  *      Returns: 0 on success, not 0 on failure
 221  *
 222  */
 223 int i2c_set_bus_speed(unsigned int);
 224
 225 /*
 226  * i2c_get_bus_speed:
 227  *
 228  *  Returns speed of currently active I2C bus in Hz
 229  */
 230
 231 unsigned int i2c_get_bus_speed(void);
 232
 233 #endif  /* _I2C_H_ */